Ask Mr. Smarty Plants

There are several milkweed vines (Family Asclepiadaceae) that have leaves that look similar to those of Matelea reticulata (Green milkweed vine).  Here is the USDA Plants Database County Distribution Map for Texas for Matelea reticulata.  The pods, holding the seeds, are called follicles.

Cynanchum racemosum var. unifarium (Talayote) has similar leaves and smooth green follicles.  The USDA Plants Database County Distribution Map for Texas shows it occurring in Blanco County adjacent to Bexar County.

Photos of the follicles of Funastrum cynanchoides ssp. cynanchoides (Fringed twinevine) are difficult to find, but Southeastern Arizona Wildflowers has photos of Funastrum cynanchoides (without the subspecies indicator), including photos of the follicles. The USDA Plants Database County Distribution Map for Texas shows it in Comal County adjacent to Bexar County.  Shinners & Mahler's Illustrated Flora of North Central Texas on p. 283 says that the follicles of Funastrum are smooth.  There is a line drawing on p. 285.

Matelea gonocarpos (Anglepod) has a follicle without bumps on the exterior but does have ridges—thus the common name of Anglepod.   Here are photos from Vanderbilt University showing the pod.  The USDA Plants Database County Distribution Map for Texas shows it occurring in Kendall and Comal Counties adjacent to Bexar.

Matelea cynanchoides (Prairie milkvine) has leaves that look a bit like those of Matelea reticulata and does occur in Bexar County according to the USDA Plants Database County Distribution Map for Texas.  The photos shown on the Louisiana Department of Wildlife and Fisheries webpage shows what appears to be smooth follicle.  However, the description in Correll & Johnston Manual of the Vascular Plants of Texas (p.1238) describes the follicle as being "more or less muricate" (muricate = "covered with short hard protuberances" according to the University of North Carolina Plant Information Center's Botanical Dictionary).

Cynanchum laeve (honeyvine) has a similar leaves and a smooth follicle; but  the nearest reported occurrence to Bexar County on the USDA Plants Database County Distribution Map for Texas is in Travis, Bastrop and Gonzales Counties. 

There may be enough in the photos and information above to determine which milkweed vine you have found.  If not you might be able to separate your plant from the other species by comparing other features such as leaf arrangement of the presence of hairs on the leaves and stems.  In Shinners & Mahler's Flora of North Central Texas, from pages 281 through 286, there are descriptions and line drawings of all of the above species.  You might also save the follicle and its seeds and try growing them next year to see its flowers.  Visit MonarchWatch.com for information about propagating milkweed seeds.

We no longer accept photographs of plants for identification because we did not have enough staff or volunteers to handle the volume of photos we received.  We do, however, show links on our Plant Identification page to several plant identification forums that will accept photos for identification.